So here's who I think look alike.

Valt-Masamune. There hair is so much alike it's really just different colored.

Tobio and Rantaro. It's because of there lollipops and blonde hair.

Kyoya and Ken. Well one they both have a fang. Two there hair is a lot alike.

Yu and Free. They look so much alike.

So I think that's it for now.